经过评估，专家小组认为在建议的使用条件下该添加剂对目标物种、消费者和环境是安全的。部分原文报道如下：

 

  Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the safety and efficacy of l-cysteine and l-cysteine hydrochloride (monohydrate and anhydrous) as flavouring feed additives for all animal species. The use in feed of l-cysteine and l-cysteine hydrochloride (monohydrate and anhydrous), produced by electrochemical reduction of l-cystine, was considered safe for the target species when supplemented at concentrations up to 25 mg/kg complete feed. The FEEDAP Panel considered that the use of l-cysteine and l-cysteine hydrochloride (monohydrate and anhydrous) in animal nutrition is safe for the consumers of products from animals receiving the additives, and to the environment. Regarding user safety, l-cysteine was not considered a skin and eye irritant nor a skin sensitiser. The additives l-cysteine hydrochloride anhydrous and l-cysteine hydrochloride monohydrate are corrosive to eyes and respiratory tract, but no conclusion can be reached on their skin irritation potential; therefore, any exposure is considered a risk. As l-cysteine and l-cysteine hydrochloride are used in food as flavouring compounds, it is expected that they can provide a similar function in feed, and no further demonstration of efficacy is necessary under the proposed conditions of use.